Lxxk r released by inertia member



March 22, 1955 G PROLA ET AL SELF-LOADING FIREARM WITH PIVOTED LOCKRELEASED BY INERTIA MEMBER 6 Sheets-Sheet 1.

Filed May 31, 1950 an a k% INVENTORJ' -PPv/a- Pro/g March 22, 1955 G.PROLA ETAL 2,704,491

SELFLOADING FIREARM WITH PIVOTED LOCK RELEASED BY INERTIA MEMBER 6Sheets-Sheet 2 Filed May 31, 1950 March 22, 1955 e. PROLA ETALSELF-LOADING FIREARM WITH PIVOTED LOCK RELEASED BY INERTIA MEMBER 6Sheets-Sheet 5 Filed May 31, 1950' March 22, 1955 G PROLA ETAL 2,704,491

SELF-LOADING FIREARM WITH PIVOTED LOCK RELEASED BY INERTIA MEMBER FiledMay 51, 1950 6 Sheets-Sheet 4 ar/o Pro/q,

whh ws fond March 22, 1955 G. PROLA ETAL 2,704,491

SELF-LOADING FIREARM WITH PIVO'I'ED LOCK RELEASED BY INERTIA MEMBER 6Sheets-Sheet 5 Filed May 31, 1950 March 22, 1955 OLA ET AL 2,704,491

G. PR SELF-LOADING FIREARM WITH PIVOTED LOCK RELEASED BY INERTIA MEMBERFiled May 31, 1950 6 Sheets-Sheet 6 INVENTOR. 6 0744-260 Frau/m2,704,491 Patented Mar. 22, 1955 SELF-LOADING FIREARM WITH PIVOTED LOCKRELEASED BY INERTIA MEMBER Goifredo Prola and Carlo Prola, Rome, ItalyApplication May 31, 1950, Serial No. 165,174

Claims priority, application Italy March 16, 1950 3 Claims. (Cl. 89-182)The present invention relates to improvements in firearm, and moreparticularly to self-loading firearm with fixed barrel.

It is an object of the present invention to provide a self-loadingfirearm with fixed barrel, wherein the unlocking of the breech bolt isprevented at the time of the discharge of the cartridge while the shotis yet into the barrel, by means of an inertia member, which first movesforward by a little extension against the resistance of a spring andthen recoils engaging the breech-bolt and carrying it rearwardly in anopening position.

Another object of the invention is to provide a selfloading firearm withwell balanced fixed barrel, with a shortened receiver and having thecenter of gravity near the handling zone.

Still another object of the invention is to provide a selfloadingfirearm with fixed barrel having two triggers and a magazine formed withtwo tubular containers disposed side by side, from which the cartridgesmay be fed by pressing either trigger so as the shooter, at the time ofthe discharge, by pressing one of the two triggers, determinesbeforehand from which container will be fed the next cartridge. In thisway, the cartridges contained in a container of the magazine may be alsodifferent from the cartridges contained in the other container.

A further object of the invention is to provide a selfloading firearmhaving a magazine for the cartridges, wherein an untimely feeding of thecartridge from the magazine is prevented.

With these and other objects in view, as will appear from the followingdescription and drawings, the invention consists in the novel featuresof constructions, combination of elements and arrangement of partshereinafter to be fully described and pointed out in the appendedclaims.

A preferred embodiment of the invention is illustrated in theaccompanying drawings wherein:

Fig. 1 shows a general longitudinal view of the firearm;

Fig. 2 shows a longitudinal view, partly in section, of the receiverwhen the firearm is ready for the discharge, the side being removed;

Fig. 3 shows a transverse section of the firearm taken along lineIII-III of Fig. 2;

Fig. 4 shows a longitudinal view of the receiver just after thedischarge, when the inertia member has ended its forward displacement;

Fig. 5 shows a longitudinal partial view of the receiver of the firearmwhen the inertia member, at the beginning of its rearward displacement,unlocks the locking block;

Fig. 6 shows a longitudinal view of the receiver when the inertia memberhas ended its rearward displacement and the ejection of the shelloccurs;

Fig. 7 shows a longitudinal partial view of the receiver at the timewhen the cartridge carrier raised with the cartridge and the inertiamember is made free from the carrier rear tooth,

Fig. 8 shows the retired position of the dog at the end of the recoil ofbreech-bolt in the event that the shooter has not withdrawn the fingerfrom the trigger;

Fig. 9 is a perspective view of the trigger-plate supporting thecartridge transfer members, the dog and the safety device;

Fig. 10 is a partial perspective view of the safety device, one triggerand T-shaped lever for the stopping of the cartridge;

Figs. 11 and 12 are perspective views of the rear end of the magazine;

Fig. 13 shows a rear view, partly in section, of the magazine;

Figs. 14 and 15 illustrate the butt-stock and the device for the handdisplacement of the inertia member.

The firearm (Fig. 1) includes a barrel 1, a frame or receiver 2, with atrigger-plate mounted in the underside of the receiver, a butt-stock 4and the magazine 5 for the cartridges.

The barrel 1 is screwed to the receiver and it is fixed by means of alatch 9, serving inside the receiver as an abutment to the breech-boltwhen in locking position. The latch 9 is operable from the outside ofthe barrel at the left hand side. On the barrel (Fig. 1) are disposedthe sight 68 and a projection 69 whereon the magazine 5 is pivoted. Aspring ring 10, slightly undulated is between the barrel and thereceiver to prevent clearance due to wear.

The receiver 2 extends rearwardly in a cylindrical tube 15 wherein thebutt-stock 4 is mounted, provided with a plate 72, the butt-stock beingfixed to the tube 15 by means of a screwed plug 70. (Figs. 14 and 15.)The receiver 2 has an opening in the underside which is closed by thetrigger plate 3, fixed to the receiver by means of the latch 14 and aside opening 17 which serves as ejection-opening for the shell.

Inside the receiver there are two grooves 11 in which the ribs of thebreech-bolt slide, a groove 76 in which the tooth of the ejector slides,a groove 12 in which the tooth 13 of the locking block 7 slides and astep 57 to abut the rear wall 16 of the locking block 7 when thebreech-bolt is locked. The receiver has also a tooth 99 (Fig. 3)projecting inwardly on which the head of inertia member 8 abuts ondischarge on the firearm. The breechbolt 6, of small dimensions, has thefiring pin 55, inclined with respect to the breech-bolt axis, theextractor 56 and the ejector 75. In the rear portion of the breechboltthere is a cavity 77 into which penetrates the cylindrical head 73 ofthe locking block 7, so as to permit the latter to rock in a verticalplane, with respect to the breech-bolt 6. The locking block 7 includes acylindrical wall which serves to close the ejection opening 17 andrearward are two projections 59 and 61 extending downwardly. Projection59 is disposed along the axis of the firearm and is in the shape of ahook, which engages a tooth 68 of the inertia member 8, whereas againstthe projection 61 abuts the step 62 of the inertia member 8. Lockingblock 7 has on the side wall a tooth 13 which slides in groove 12 of thereceiver 2.

The inertia member 8 is a heavy cylindrical bar, sliding in the tube 15,and is intended to carry rearwardly the breech-bolt by engagement of itstooth 60 with the projection 59 of the locking block and to carryforwardly, in locking position, the breech-bolt 6 urging by its step 62the projection 60 of the locking block. In its rear portion the inertiamember is axially bored to receive the action-spring 18, guided by rod71 fixed to plug 70 (Figs. 14 and 15). In the underside the inertiamember 8 has a fiat surface 78, which rides the 3 and prevents theinertia member its axis.

The head 49 of the inertia member 8 is so shaped as to engage tooth 35of the cartridge-carrier 32, which tooth, when raised, causes the member8 to remain in rear position keeping the breech-bolt in openingposition. Along the flat surface 78 of the member 8 is provided a groove79, wherein tooth 35 of the cartridge carrier slides during the motionof member 8. In the central cylindrical portion the member 8 has acavity 48, where in penetrates the head 47 of lever 44 (Figs. 14 and 15)for the hand operated opening of the breech-bolt. In the vertical wall101 of the member 8 a cavity 80 is bored in which is located the piston64 with a strong spring 65, which plston may penetrate into the cavity80 by an extension corresponding to the length of the slot 81 providedin piston 64. Piston 64 is secured by a key 82.

In the underside of the buttstock 4 there is arranged the device whichpermits hand opening of the breechbolt when the chamber is clear and itis desired to introduce a cartridge therein. Such device includes alever wall 98 of trigger plate 8 from rotation around 41 pivoted on thehorizontal shaft 42. Lever 41 has a projection 43 on which a lever 44 ispivoted, which has at its end a cylindrical head 47. On the stern oflever 41 two beads 45 are applied, which penetrate in the recess 46 ofthe butt-stock and keep the lever against the underside of thebutt-stock. By raising lever 41 it rocks on shaft 42 and carries lever44 with it, which engage by the head 47 the cavity 48 in the inertiamember 8. Upon continuing to raise lever 41, head 47 carries inertiamember 8 rearwardly in the cylindrical tube 15 by an extension of about80 mm. until head 49 (Fig. 6) of member 8 engages tooth 35 of thecartridge-carrier 32, which prevents the forwardly return of member 8.At this time, head 47 is hand disengaged from cavity 48 and lever 41 maybe again depressed inside the underside of buttstock 4; the breech-bolt6 remains in opening position and one cartridge is hand introduced inthe barrel.

Trigger plate 3 bears the members for the discharge of the cartridge,the cartridge carrier and the safety device. Trigger plate 3 is engagedin the receiver 2 by means of grooves and is locked at the rear by meansof pin 14 controlled by the outer bolt 19. Trigger plate 3 supports thehammer 20 urged by spring 21, guided by rod 22. The hammer 20 hasrearward a hook 83 which engages, when the spring is compressed, thetooth 84 or the tooth 85 of the bifurcate lever 23, urged by spring 67,fixed to the trigger-plate. Two triggers 24 and 25 pivoted on plate 3,have a finger piece 86, a rear projection 26 for controlling sear 23 anda forward arm 27. Arms 27 of the two triggers act on beads 52 and 53(Figs. 1 and 2) of the levers 28 and 29, each of which stops the feedingof the cartridge from the containers of magazine by means of two teeth87, 88, alternately, made in each lever. Beads 52 and 53 may be alsohand controlled when the magazine is rocked away from the barrel. Theprojection 26 extends rearwardly in a tail 89, which is engaged by theteeth 39 of the latching plate 38 of the safety device which is pivotedon a vertical stud 40 (Fig. 2). The disengagement of the teeth 39 fromthe tail 89 of the trigger is effected when the firearm is handled bypressing against an outer member 90 of the plate 38. Member 90 may belocked by a stop, not shown, operable by hand. The forward portion ofthe plate 3 carries a latch 30 with a spring 31, which locks themagazine 5 against the barrel. The rear portion of trigger plate 3 has awall 98 extending upwardly whereon slides the flat surface 78 of theinertia member 8, preventing this latter from rotation around its axis.On trigger plate 3 there is mounted the cartridge carrier 32 shaped as afork pivoted in its realpart on the shaft 34 (Fig. 4) and urged upwardlyby a spring 33. A spring urged stop 74, made with two arms angularlydisposed, and controlled both by tooth 36 and by bead 54, has a hook 91which keeps the cartridge carrier in depressed position. In its rearpart the carrier 32 has pivoted a spring urged tooth 35, which keeps theinertia member at the end of the movement rearwardly, when the carrieris depressed.

On the shaft 92 a T-shaped lever 93 is pivoted, which passing, forward,between the arms of the fork of the carrier 32 puts the transverseelement of lever 93 in front of the magazine 5 beyond the forward end ofthe carrier. The T-shaped lever is intended to prevent for a certaintime the cartridge from coming out of the magazine before beingpermitted to ride the carrier. The forward end of the T-shaped lever isdepressed to permit the cartridge to ride on the carrier by means of aprojection extending downwardly from the hammer 20 which presses thebracket 96 applied to the side of the T-shaped lever (Fig. when thehammer has been again hooked rearwardly by the breech-bolt 6 which hasrecoiled.

The magazine 5 for cartridges comprises two tubular containers 95disposed side by side and may be moved away from the barrel by rockingon the projection 69 of the barrel, being urged by a spring which iskept pressed when the latch 30 of trigger plate 3 penetrates in thecavity 94 of the magazine. Each tubular container 95 has a spring 51(Fig. l) for urging out the cartridges. The cartridges are retainedinside the containers 95 by means of a locking and releasing lever 28,29 which operates in different manners depending upon whether theshooter, after having pressed the trigger, withdraws his fingertherefrom or keeps the trigger pressed. If the shooter withdraws hisfinger from the trigger, the end of the arm 27 raises, discontinuing itspressing on bead 52 or 53 and permitting the lever 28 or 29 to rockupwardly under the urging of spring 97. In this manner, the stopping ofthe cartridge occurs by means of tooth 87 of the lever. If the shooter,on the contrary, after the discharge, keeps a finger pressed against thetrigger, the end of arm 27, and consequently bead 52 or 53 remainsdepressed, the lever 28 or 29 cannot rock upwardly and the cartridge isheld inside the container 95 by means of tooth 88 of the lever (Figs. 11and 12). In this second case, since the trigger is kept pressed, thehammer, which is moved in the retired position by the breech-bolt 6which recoils, cannot engage its hook 83 with tooth 84 of the sear 23since the latter is rocked downwardly. The engagement is then made bytooth 85 of sear 23, which catches the rear part of book 83 of thehammer (Fig. 8).

The operation of the firearm will be now described assuming that thebreech-bolt is in closing position, a cartridge is in the barrel and twocartridges are in each of the two containers of the magazine (Fig. 2).In this position, the rear wall 16 of the locking block 7 abuts againstthe step 57 of the receiver 2 and keeps the breechbolt 6 closed. Theforward portion of the inertia member 8 is under the locking block 7 andunless the inertia member 8 moves rearwardly, the locking block 7 cannotlower and permit the unlocking of the breech-bolt.

The shooter, in handling the firearm with the left hand, presses themember 90 of the safety plate 38, whereby the teeth 39 are moved awayfrom the tails 89 of the trigger which may be operated (Fig. 10).

Since the pressing of one of the triggers controls the movement of acartridge, for the next discharge, from one of the two containers 95,the shooter has previously to determine which of the two triggers has tobe operated and this particularly when the cartridges of the twocontainers of the magazine are different. The operation of trigger 24,for instance, causes the rocking of sear 23, which disengages its tooth84 from hook 83 of hammer 20. The latter, urged by spring 21 rocksforwardly and strikes the firing pin 55, causing the discharge to occur(Fig. 4). At the same time, trigger 24, by means of its forward arm 27,presses bead 52 of the lever 28, which rocks thereby lowering tooth 87which frees the first cartridge of a container which cartridge is urgedrearwardly by spring 51 toward the cartridge carrier 32, but beingprevented from riding thereon because it is stopped by the transversearm of the T-shaped lever 93 (Fig. 4) which is in raised position.

At the time of the discharge, the whole firearm recoils and therewiththe breech-bolt 6 and the locking block 7 which are fixed to the barrel.The inertia member, on the contrary, due to inertia, will effect aforwardly movement by pressing the spring loaded piston 64 by anextension corresponding to the length of the slot 81 till the surface101 abuts against the wall 96 of the receiver 2 (Fig. 4). During theforward movement of the inertia member 8, its forward part is under thelocking block 7 and abuts against tooth 99 (Fig. 3) and prevents thelocking block from lowering which would cause the unlocking of thebreech bolt 6. When the surface 101 is in contact with the wall 96, theinertia mass partakes of the movement of the firearm, but, while thislatter is stopped by the shoulder of the shooter, urged by the spring 65of piston 64 which is now extending, continues its movement rearwardlycompressing the action spring 18 (Figs. 14 and 15) and carrying with it,through its tooth 60 engaged with projection 59 the locking block 7 andthe breech-bolt 6, after the locking block 7 has lowered so as to causethe wall 16 to become free from the step 57 of the receiver (Figs. 5 and6). During the movement rearwardly, breech-bolt 6, by means of theextractor 56 withdraws from the chamber the shell, which, struck by theejector 75, is ejected through the ejection opening 17, which in themeantime has been cleared owing to the recoil of the locking block 7(Fig. 6). The inertia mem ber recoils till the action spring 18 iswholly compressed and is retained in its rearmost withdrawn position bytooth 35 of the cartridge carrier. The breech-bolt 6, during its recoilabuts against hammer 20, which is rocked rearwardly until its hook 83 isagain engaged by tooth 84 or 85 of the sear 23. The hammer 20 inreturning to its rearmost position causes T-shaped lever 93 to lowerthus permitting the cartridge 100 to ride the carrier 32, striking thestop tooth 36, which moving back, disengages its hook 91 from thecartridge carrier permitting the latter, by rocking on pivot 34 to raiseits forward part carrying the fresh cartridge in front of the barrel(Fig. 7).

The raising of the carrier causes tooth 35 to be lowered, so that theinertia member 8, no further retained by said tooth (Fig. 7) may moveforwardly urged by spring 18, pushing forward the locking block 7, bymeans of the surface 62 which abuts against the projection 61 of thelocking block, and the breech-bolt which introduces the fresh cartridgein the chamber of the barrel. The inertia member 8 finds the carrierempty and sliding thereon causes it to lower and to be restored inposition in front of the magazine.

We claim:

1. In a self-loading firearm having a barrel fixed with respect to areceiver, a receiver having grooves therein, a breech-bolt arranged toslide in said grooves in said receiver, said breech-bolt being providedwith a rear recess of circular cross-section, a locking block having tworear projections extending downwardly and a forward cylindrical headrockably engaged with said rear recess, said locking block, when in theupper position, being aligned with the breech-bolt and abutting with therear end against a vertical step in the wall of the receiver to hold thebreech-bolt in barrel closing position, an inertia member movable from aforward position corresponding to the closing of the breech-bolt to arearmost position corresponding to the opening of the breech-bolt, saidinertia member being arranged to engage one of said projections to rockdownward the locking block with respect to the breech-bolt and towithdraw the locking block and the breech-bolt therewith and to abutagainst a second of said projections to push forward and to rock upwardthe said locking block to restore the latter in alignment with thebreech-bolt and in engagement with the vertical step of the receiver,said inertia member having a vertical Wall with a cavity therein, aspring loaded piston located in said cavity bored in said vertical wallof the inertia member, said piston being arranged to distance the saidvertical wall of the inertia member from a fixed surface of the receiverand to permit said vertical wall to touch with said surface when thepiston loading spring is compressed at the discharge of the firearm.

2. In a selfloading firearm a receiver having grooves, 21 barrel fixedto said receiver, a breech-bolt provided with ribs sliding in saidgrooves of said receiver, said breech-bolt having a rear recess having acircular cross section, a locking block having a forward cylindricalhead engaging said recess and arranged to rock in a vertical plane froman upper to a lower position and back, two rear projections on saidlocking block extending downwardly, said locking block, when in upperposition, being in alignment with said breech-bolt and abutting at therear end against a vertical step in the wall of the receiver to hold thebreech-bolt in a barrel closing position, an inertia member arranged toengage said projections of the locking block for withdrawing the lockingblock and the breech-bolt therewith and for restoring the locking blockin the upper position and the breech-bolt in barrel closing position,the inertia member with its forward end, when the breech-bolt is inbarrel closing position, being located under said locking block toprevent the same from rocking downward on the discharge of the firearm,said inertia member having a vertical wall with a cavity bored thereinand having the axis parallel to the axis of the inertia member, a springloaded piston located in said cavity and projecting therefrom todistance the vertical wall of the inertia member from a verticalprojection fixed to the receiver, whereby the inertia member on thedischarge of the firearm and at the beginning of the recoil of thelatter moves forward to compress the piston loading spring until thevertical wall of the inertia member abuts against the verticalprojection of the receiver and then moves rearward together with therecoiling firearm, said spring loading the piston while extendingcausing the rearward movement of the inertia member with respect to thefirearm to the rearmost position of the inertia member when the firearmis stopped.

3. In a self-loading firearm having a receiver and a barrel fixedthereto, a breech-bolt, a locking block engaged with the breech-bolt,the locking block being arranged to rock with respect to the breech-boltto assume two different positions in a vertical plane, an upper positionwherein the locking block is aligned with the breech bolt to keep thelatter in a barrel closing position by abutting against a vertical stepin the wall of the receiver, a lower position wherein the locking blockis downwardly rocked with respect to the breech-bolt, an inertia memberto engage the locking block both during the forward and the rearwardmovement of the inertia member, said inertia member having a verticalwall and having a cavity bored in said vertical wall, a projection fixedto the receiver facing said vertical wall, a spring piston located insaid cavity and projecting therefrom to distance said vertical wall fromsaid projection and arranged to allow the vertical wall to abut againstsaid projection on the discharge of the firearm through compression ofthe spring of said piston, two projections in the rear portion of thelocking block extending downwardly, one of which engages the inertiamember during rearward movement of the latter and the other engages theinertia member during forward movement of the latter, the inertia memberin its forward position being arranged to abut its forward end under thelocking block to prevent the latter from rocking downwardly with respectto the breech-bolt, the inertia member holding the locking block and thebreech-bolt in barrel closing position on discharge of the firearm byits forward movement through compression of the piston loading springand withdrawing the locking block and the breech-bolt therewith when thevertical wall of the inertia member abuts against the verticalprojection of the receiver continuing its rearward movement, when therecoil of the firearm due to the discharge is stopped, under the actionof the spring loading the piston during restoring of said spring in theextended position.

References Cited in the file of this patent UNITED STATES PATENTS1,147,780 Borchardt July 27, 1915 2,333,677 Roemer Nov. 9, 19432,418,946 Loomis Apr. 15, 1947 2,466,902 Lochhead Apr. 12, 19492,480,074 Browning Aug. 23, 1949 2,506,982 Williams May 9, 19502,626,475 Browning Jan. 27, 1953 2,634,536 Sefried Apr. 14, 1953 FOREIGNPATENTS 540,879 Great Britain Nov. 4, 1941

